EPJ B Highlight - Simulating better performance in piezoelectric energy harvesters
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- Published on 21 October 2025
Analysis explains how nonlinear piezoelectric devices are far better than their linear counterparts at harvesting energy from noisy vibrations across a broad range of frequencies
Over the past few decades, the capabilities of piezoelectric energy harvesters have steadily improved, paving the way for micro- and nano-electronic devices which can be powered directly from the energy of ambient, noisy vibrations in their surrounding environments. So far, however, these devices have only been able to harvest from vibrations within a narrow frequency range, severely limiting their performance in real-world scenarios.
Through new analysis published in EPJ B, Martín Giuliano and Alejandro Sánchez at the National University of Mar del Plata, Argentina, show how this performance could be improved by integrating nonlinear dynamics into piezoelectric energy harvesters – allowing them to capture the inherently broad spectrum of frequencies associated with noisy vibrations. The duo’s findings could help guide the development of next-generation energy harvesters, making them far more autonomous than existing designs.
EPJ B Highlight - Calculating the impact of domain walls on systems’ free energies
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- Published on 17 October 2025
Mathematical approach improves calculations of how phase boundaries affect a material’s properties
The behaviours of many materials are strongly influenced by abrupt boundaries between different phases, called domain walls. In particular, the patterns in which domain walls arrange themselves are closely connected to a material’s free energy: a temperature-dependent quantity representing the balance between a system’s tendency toward low energy and high entropy.
Through new analysis published in EPJ B, a collaboration of European researchers have developed and applied a method that accounts for all possible arrangements of domain walls within a model system. By providing a robust approach for calculating its free energy, including finite-size effects, their method could help improve models of a wide array of structures where domain walls play a key role.
EPJ B Topical Issue - Recent Advances in Complex Systems
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- Published on 01 October 2025
Guest Editors: Thiago B. Murari, Marcelo A. Moret, Hernane B. de B. Pereira, Tarcísio M. Rocha Filho, José F. F. Mendes, Tiziana Di Matteo
Inspired by the Conference on Complex Systems 2023 (CCS2023) in Salvador, Brazil, this collection of EPJ B brings together 25 peer-reviewed articles covering a wide range of topics.
This collection highlights the interdisciplinary nature of the field, with contributions from physics, biology, economics, linguistics, and artificial intelligence, and serves as a reference for researchers addressing real-world challenges through systems-based thinking.
EPJ B Highlight - Unlocking next-gen optoelectronic with InSb/WSSe heterostructures
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- Published on 22 August 2025
Alternating layers of the 2D semiconductors could yield materials with advanced optical absorption properties—especially in the visible range
Due to their unique geometries and quantum properties, atom-thick 2D semiconductors have transformed the landscape of materials science, placing them at the forefront of fields including electronics, photonics, and energy conversion. Recently, these capabilities have been extended by stacking different 2D semiconductors into van der Waals heterostructures, which exhibit light-detecting and controlling abilities not seen in bulk materials.
In new research published in EPJ B, Weibin Zhang and colleagues at Yunnan Normal University demonstrate that heterostructures made from alternating layers of InSb and WSSe are highly suited for light absorption. If confirmed experimentally, these properties could make the material a valuable platform for harvesting light across a broad range of wavelengths—potentially paving the way for next-generation optoelectronic devices.
EPJ B Highlight - Uncovering the magnetic responses of anisotropic semimetals
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- Published on 14 July 2025
Calculations show that magnetic fields can alter the responses of anisotropic 2D semimetals to electric fields and temperature gradients – but only when applied perpendicular to the material’s plane
For solid-state physicists, graphene has become a posterchild of 2D semimetals: materials whose electronic structures fall between those of a metal and a semiconductor. Owing to the honeycomb structure of its carbon atoms, graphene hosts an orderly arrangement of Dirac cones – pairs of opposite-facing, cone-shaped energy bands that touch at a single point. Immediately surrounding such a point, electron energy varies linearly with momentum, just like for massless particles such as photons – leading to exotic and often useful electronic properties.
Through a new paper published in EPJ B, Ipsita Mandal at the Shiv Nadar Institution of Eminence, India, presents fresh calculations of how these properties vary in the presence of magnetic fields, particularly when 2D semimetals are structurally distorted. Her results show that these materials’ electrical and thermal responses are affected only when the magnetic field is oriented perpendicular to the 2D plane. This finding offers deeper insight into the electronic behaviour of semimetals – potentially broadening their already wide range of technological applications.
EPJ B Highlight - Understanding 2D Dirac semimetals in tilted magnetic fields
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- Published on 09 July 2025
Model reveals that within ultrathin Dirac semimetal films, the transport of quantised Dirac fermions can occur in two distinct ways, depending on how the film is tilted relative to an applied magnetic field
Dirac matter is an exotic phase of matter in which quasiparticles – arising from low-energy electron excitations behave like relativistic particles – obey the rules of both quantum mechanics and special relativity. Among these systems are materials called Dirac semimetals, which are characterised by discrete points where their conduction and valence bands touch, forming a linear energy–momentum relationship. Today, physicists are especially interested in the unusual topological phases that can emerge when Dirac semimetals are fabricated into ultrathin 2D films.
Through theoretical analysis published in EPJ B, Rui Min and Yi-Xiang Wang at Jiangnan University, China, investigate how Dirac fermions are transported in thin semimetal films under tilted magnetic fields. Their model reveals that the quantum Hall behaviour of these materials changes in distinct ways depending on the field’s orientation – offering new insights into the topological nature of Dirac matter. Their results could lead to applications in areas including quantum computing, low-power electronics, and spin-based information processing.
EPJ B Highlight - Predicting adsorption with quantum indicators
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- Published on 27 June 2025
A new mathematical framework predicts how solid materials adsorb to surfaces, using five quantum-based indicators of their constituent atoms
Many areas of research are challenged by the need to explain the properties of materials based on the quantum behaviour of their atoms. One particularly difficult effect to describe is the adsorption of solid materials onto other solid surfaces. Currently, this is often approached using band-based models, which consider groups of electron energy level, or ‘bands’, in the atoms that make up a material. However, these models have limited accuracy, especially when trying to connect quantum details with practical outcomes.
In new research published in EPJ B, Yonghui Li and colleagues at Tianjin University, China, introduce a method that more accurately predicts how strongly atoms in a material will adsorb to other surfaces. Their approach is based on a set of five key indicators, offering a more complete picture of how adsorption is controlled by atomic electron bands. This could have wide-ranging applications in areas such as materials design, catalysis, and biological systems.
EPJ B Topical Review - High critical current densities of body-centered cubic high-entropy alloy superconductors: recent research progress
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- Published on 30 April 2025
High-entropy alloys (HEAs) represent a novel paradigm in materials science. HEAs demonstrate a wide array of functionalities, including outstanding mechanical properties, superior corrosion resistance, and durable hard coatings. HEA superconductors have attracted considerable attention due to their distinctive attributes, such as robust superconductivity under extreme conditions and high critical current densities. Several body-centered cubic (bcc) HEAs have shown critical current densities comparable to those of commercial Nb-Ti superconducting alloys. HEAs possess the extraordinary capability to integrate multiple functionalities—a feature seldom observed in conventional alloys. Consequently, bcc HEA superconductors with elevated critical current densities are highly promising for practical applications in extreme environments, such as aerospace and nuclear fusion reactors, owing to the exceptional irradiation resistance characteristic of HEAs.
EPJ B Highlight - Modelling the electronic structure of single-doped perylene
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- Published on 15 April 2025
The molecule perylene has exciting applications in the fields of organic electronics and astronomy
The molecule perylene has become of great interest to scientists developing organic electronics and technology which harnesses organic molecules or polymers with electronic properties like conductivity. Perylene has uses ranging from the creation of organic semiconductors to organic light-emitting diodes (OLEDs) to even building organic solar cells. In addition to this, perylene is of great interest to astronomers, as this molecule has been discovered in interstellar gases and nebulae, granting insights into the powerful cosmic events that forged and dispersed it.
EPJ B Highlight - Understanding speech with a new model of word recognition
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- Published on 15 April 2025
Researchers found some surprising differences in the way humans handle long and short words
A new dynamical model of speech recognition has revealed the very different ways that humans perceive short and long words in everyday speech. The authors of the research published in EPJ B, Jean-Marc Luck of the Université Paris-Saclay and Anita Mehta, formerly of the Faculty of Linguistics, Oxford and currently at St Catherine’s College, University of Oxford, take a radically different approach to speech perception.
